1. Field of The Invention
The present invention relates to an air cleaner, and more particularly, to an air cleaner provided with an engagement maintaining mechanism for maintaining engagement of a cover capable of improving maintenance or like workability at a time of exchanging a filter element.
2. Related Art
In a conventionally known air cleaner for an internal combustion engine, a case and a cover are mutually connected by means of hinge structure constructed by a hinge and a hinge receiver, and these members are rotated to be opened or closed.
In the air cleaner of this structure, an intake port is formed to either one of the case or cover and an exhaust port is formed to the other one thereof. The intake port and the exhaust port are constructed such that an outer edge of the filter element is held by the case and the cover so as to be communicated with each other through the filter element, which is disposed between the case and cover.
Since the filter element is provided with a function for filtrating outer (ambient) air taken into the internal combustion engine, it is necessary to periodically exchange the filter element with new one because the filtrating function becomes deteriorated for a long time use of the internal combustion engine. Such filter element exchanging working is generally performed under a condition such that the air cleaner is disposed in an engine room of an automobile in which an internal combustion engine and many other machineries or components, and under the condition, if the filter element is exchanged, in a certain case, it is impossible to visually observe the engaging condition of the hinge structure between the case and the cover, and in an adverse case, the filter element exchanging working may have been completed with the hinge structure being disengaged, which results in insufficient achievement of desired air cleaning function, thus being inconvenient.
In order to obviate such defects, there are many methods and countermeasures have been proposed such as disclosed in:                Patent Document 1: Japanese Patent Application Laid-open Publication No. 2005-36701        Patent Document 2: Japanese Patent Application Laid-open Publication No. 2005-61382        
An air cleaner disclosed in the above Patent Document 1 has a case in which a filter element is housed and a cover for opening or closing an opening (opened portion) of the case. The case is provided with a receive-side engaging portion and the cover is provided with an engaging portion which is engageable with the receive-side engaging portion of the case. The engaging portion of the cover is formed with an arm projecting from an outer peripheral edge of the cover and a pivot integrally formed with the arm so as to be pivotal around the arm, and on the other hand, the receive-side engaging portion is formed with a pivot support portion for supporting the pivot and an arm support portion supporting a peripheral surface of the arm from the side opposing to the pivot support portion. The pivot support portion and the arm support portion forms a pocket into which a predetermined range of the pivot and arm is fitted into the pocket such that the predetermined range of the pivot and the arm are constrained by the pocket, and the pivot can be maintained to a predetermined position under the condition where the cover and the case are closed and are opened at a predetermined angle. The air cleaner of the Patent Document 1 has such structure as mentioned above.
On the other hand, an air cleaner disclosed in the Patent Document 2 is provided with: one case having a seal surface formed on a peripheral edge of an opening; another case detachable with respect to the opening of the one case; a filter member disposed in either one of the above two cases and having a peripheral seal portion held between seal surfaces of both the cases; a movement restricting member disposed between both the cases for restricting or limiting relative movement in a direction approximately perpendicular to an attaching (detaching) direction of both the cases; and a holding member disposed between both the cases for holding both the cases in a state holding the peripheral edge portion of the filter member.
The air cleaner of the Patent Document 2 further includes a distance restricting or limiting member, which is provided at a portion along at least an attaching (detaching) direction if both the cases of both the seal surfaces, for restricting a distance between both the seal surfaces at the time of attaching (detaching) of both the cases so as to avoid interference between the seal portion of the peripheral edge of the filter member and either one of both the cases.
However, according to the structures of the conventional air cleaners mentioned above, the hinge structure is made enlarged, thus being improper for making compact the structure of the air cleaner.